1. Technical Field
The disclosure relates to an antifogging device for preventing fogging of an objective lens. The disclosure also relates to an endoscope device having the antifogging device and configured to be introduced into a living body to acquire images in the living body.
2. Related Art
In a medical field, an endoscope device is conventionally used for observing an organ of a subject such as a patient. The endoscope device includes an insertion portion inserted into a body cavity of the subject, an imaging unit provided on a distal end of the insertion portion which takes an in-vivo image, and a display unit capable of displaying the in-vivo image taken by the imaging unit. When acquiring the in-vivo image by using the endoscope device, the insertion portion is inserted into the body cavity of the subject while emitting predetermined illumination light from the distal end of the insertion portion to take an image by the imaging unit.
The imaging unit includes an image sensor and an optical system including one or a plurality of optical members such as an objective lens which condenses outside light to form an image on the image sensor. Out of the optical system, the optical member on the most distal end (herein, it is described as the objective lens) is provided on the distal end of the insertion portion with a partial surface exposed to outside. Therefore, a surface of the objective lens might be fogged due to change in temperature (for example, change from 20° C. to 37° C.) in an environment when the insertion portion is inserted into a body from outside the body of the subject, for example. There is a problem that a clear in-vivo image cannot be acquired when the surface of the objective lens is fogged.
The endoscope device provided with a heating light guide which emits light for heating based on a detection result of a temperature sensor provided on the distal end of the insertion portion provided separate from an illuminating light guide which illuminates an imaging area by the imaging unit is disclosed as technology of inhibiting fogging of the surface of the objective lens (for example, refer to JP 2003-334157 A).